Today, we meet a turtle with an iron shell. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.

The Japanese ruler Hideyoshi
invaded Korea in 1592. He was armed with a new
weapon -- muskets sold to him by the Portuguese.
Hideyoshi quickly overran Seoul and seemed to be on
his way to conquering the country. Then the Korean
government turned to Admiral Sun-Shin Yi. Yi was a
brilliant strategist who'd seen war coming and had
raised private money to construct a small fleet of
utterly remarkable ships called Turtle boats.

The Turtle was ironclad, and it looked like a
hundred-foot-long turtle. It had a low, rounded
roof, bristling with spikes to prevent boarding.
Its sails came down in battle, and it was powered
by oars. Just above the oars were ports for cannon,
small firearms, and arrows. It had features in
common with both Civil War ironclads -- the Monitor
and Merrimack -- built 250 years later. The Turtle
boats were equipped with rams as well as a dragon's
head on the prow. The dragon's head poured out
smoke to frighten the enemy and to lay a very
effective smoke screen.

During the following months, Yi tore into the
Japanese fleet of some 200 ships with his new
weapon and devastated it. The war ended in a truce,
with Korea divided.

Admiral Yi had stopped the invasion, but he had
stirred up political jealousy by doing it. His
opponents had him thrown in jail, and there he sat
until Hideyoshi renewed the invasion in 1597. With
Yi out of the way, the Japanese ravaged the Korean
navy. Yi was finally exonerated and put back in
charge of just 12 surviving warships.

Less than a month later he ambushed 133 Japanese
ships with this tiny fleet. He sank 31 of them and
drove the rest off. He also bought time to rebuild
his navy.

A year later, the Japanese were fighting a losing
war. They began a total withdrawal in an armada of
500 ships. Then Admiral Yi struck them once again
with his Turtle -- with this mad, visionary weapon.
He sank hundreds of ships -- over half the fleet.
The carnage far exceeded the slaughter in Drake's
defeat of the Spanish Armada just ten years
earlier. In fact, the Japanese loss of 50,000 men
was twice the combined number of men who'd merely
sailed in the English and Spanish fleets.

The Japanese were so badly beaten that they stayed
away from Korea until 1904. Admiral Yi was killed
in the battle. And in a strange way, so too was the
Turtle. Neither it, nor this huge naval encounter,
are even footnotes in Western history books. And we
don't see anything like the Turtle again until the
Civil War.

I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.